'Dust storms in W Asia trigger plentiful monsoons'

A bigger dust storm in a North African desert can mean plentiful rains in India, research has shown.

The interesting link between desert dust in North Africa and West Asia and stronger monsoons in India was revealed by a 10-year study carried out by scientists of IIT Bhubaneswar and researchers at Pacific Northwest National Laboratory.

The study said satellite data had shown stronger monsoon rains were recorded in India sometimes a week after a higher concentration of small particles called aerosols occurred over North Africa, West Asia and Arabian Sea.

The researchers wanted to see if they could verify this and determine how those particles might be affecting the rainfall.

Aerosols originate from a variety of sources, natural dust being one of them. Bigger dust storms over West Asia, North Africa or the Gulf Region can lead to absorption of solar radiation, the study said.

"This leads to warming of the atmosphere over a vast area, strengthening the moisture transport from Arabian Sea, thereby enhancing the monsoon rainfall over India," said Dr V Vinoj of IIT Bhubaneswar, the lead author of the study.

The strength of monsoons has been declining for the past 50 years, said Dr Philip J Rasch, chief scientist for climate at PNNL and a co-author of the paper.

"We found that dust plays a role in strengthening the monsoon, although this natural phenomenon does not overpower other influencing effects such as temperature differences between land and ocean, land use changes and the local effect of pollution around India," he said.

The scientists arrived at the result, published in March 16 edition of Nature Geoscience, after analysing data from NASA satellites and using computer climate model simulation for about 10 years.